BirdAnalyst
Species · BCR 4 · BBS 2025 Release · 1966–2024

Red-necked Grebe In BCR 4

All regionsBCR 4Wetland birds

Red-necked Grebe in BCR 4 has fallen sharply: down 74% on the route-weighted index since 1982.

-74%Since 1982TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
35Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
43YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Red-necked Grebe has fallen sharply in BCR 4: down 73% on the route-weighted index since 1982.

Red-necked Grebe In BCR 4 Population Forecast

If the recent trend holds, Red-necked Grebe in BCR 4 is projected to fall about 59% by 2029 — from 0.31 in 2024 to a central estimate of 0.13 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±41.9%, with 100% of held-out values landing inside the 95% band.

-59%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.13Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.195% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±41.9%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Red-necked Grebe in BCR 4 is projected to fall about 59% by 2029 — from 0.31 in 2024 to a central estimate of 0.13 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±41.9%, with 100% of held-out values landing inside the 95% band.19752029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.200.001.1
20260.180.001.1
20270.160.001.1
20280.140.001.1
20290.130.001.1

Routes In BCR 4

Routes recording Red-necked Grebe in BCR 4.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Goose BayALASKA51982
Kenny LakeALASKA41989
Kobuk River (Short)ALASKA41992
SlanaALASKA32022
Kanuti CanynALASKA32001
Tower BluffsALASKA22013
NorthwayALASKA22022
WillowALASKA22024
Bear CreekALASKA21991
Swan Lake RdALASKA22023
Anchor RiverALASKA21997
WasillaALASKA21983
Nicholai SlALASKA22024
KachemakALASKA22024
Hather CreekALASKA22024
Mud RiverALASKA22022
Ft. RichrdsnALASKA22010
Galena (Short)ALASKA22024
Birch LakeALASKA12019
ChistochinaALASKA12021
CantwellALASKA11999
HomerALASKA11982
Chena Hot SpALASKA11990
SourdoughALASKA11991
TonsinaALASKA12016

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.